With flu cases soaring, some Minnesota hospitals are tightening visitor restrictions for the first time since the H1N1 flu pandemic of 2009.

Their message to would-be visitors: Stay home if you're sick.

The maternity ward at Fairview Lakes Medical Center in Wyoming, Minn., is now officially off limits to visitors with cough, fever or other symptoms of the flu. At the New Ulm Medical Center, only immediate family members will be allowed to visit patients -- and only if they're healthy. Even then, they'll be limited to two visitors at a time.

Starting Wednesday, the Mayo Clinic says it plans to impose the same restrictions on visitors at affiliated hospitals in New Prague, Mankato, Fairmont, Springfield, St. James and Waseca.

Hospital officials say the measures are designed to protect vulnerable patients, as well as staff members, while the flu is spreading widely in the community. The flu can be especially dangerous to the frail or elderly, especially if they're already hospitalized for another reason.

So far, the tightest restrictions are popping up in southern Minnesota, which has been among the hardest-hit areas this flu season, according to state health officials.

Some hospitals are reporting higher numbers of flu patients than during the height of the 2009 H1N1 outbreak, according to the Mayo Clinic.

In the Twin Cities, most hospitals have not yet tightened visiting rules, but they are posting prominent new signs at entrances to discourage visitors who may be sick or infectious, according to hospital officials.

At St. John's Hospital in Maplewood, staffers have dusted off warning signs that have been in storage since the 2009 flu pandemic, said spokeswoman Allison Sandve.

Another says: "If you are sick, or any member of your household is sick, we ask that you not visit patients."

That's the standard rule year round, Sandve noted, but reminders are especially important during a flu season like this one.

As of Monday, St. John's had 16 patients in isolation with flu symptoms, an unusually high number, she said.

"We are in a situation where we're working really hard to make sure we have beds for everybody," she said.

At Regions Hospital in St. Paul, officials said they have not tightened visitor restrictions, beyond urging visitors to stay away if they're sick. But a spokeswoman said the hospital is "closely monitoring" the flu outbreak to determine if tighter restrictions are needed.

As of the end of December, nearly 600 people had been hospitalized with the flu in Minnesota, and four people had died of complications, since the start of the flu season in October.

Health officials are encouraging people to get flu shots and to take simple steps to limit the spread of the disease, such as frequent hand washing, covering coughs and staying home when sick.